Oxygen evolution reaction (OER) plays a key role in energy conversion and storage processes such as water splitting and carbon dioxide reduction. However, the sluggish kinetics caused by insufficient active surface and limited charge transfer hinder OER's wide applications. In this work, a novel self‐templating strategy for the fabrication of composite CoO–MoO 2 nanocages with enhanced OER performance is proposed. By designing a nanocage structure and incorporating conductive MoO 2 to promote both mass and charge transfer, high OER activity (η = 312 mV at 10 mA cm −2 ) as well as good stability in the resulting CoO–MoO 2 composite nanostructure can be achieved. This versatile synthetic strategy can also be extended to other metals (such as W) to provide greater opportunities for the controlled fabrication of mixed metal oxide nanostructures for electrochemical applications.